In today's era of globalization, the business environment is evolving rapidly, presenting both opportunities and challenges. This evolution is reflected in the increasingly fast-paced lifestyle, which fuels a growing demand for immediacy, particularly in the realm of food, where people now expect quick or instant service. Consequently, it is unsurprising that fast food has become a preferred choice for many. McDonald's, one of the most recognized fast food chains worldwide, has established a strong presence in Indonesia. Over the past three years, McDonald's has consistently held the second position in the Top Brands Index, just behind Kentucky, with its growth in the index outpacing that of other fast food competitors. In light of this, researchers are prompted to examine "The Determinants of McDonald's Purchasing Decisions." This study aims to identify the factors that influence customer decisions, focusing on brand image, service quality, and customer satisfaction. The research is designed as a conclusive study, a form of inferential research that tests specific hypotheses either through detailed analysis of a particular issue (descriptive) or by exploring the relationships between variables (correlative) that involve both independent and dependent variables. The findings of the study indicate that while brand image positively impacts customer satisfaction, the effect is not significant, though it does significantly boost customer loyalty. Service quality has a positive and significant effect on customer satisfaction, though its impact on purchasing decisions is positive but not significant. However, customer satisfaction has a strong positive influence on purchasing decisions. Furthermore, brand image has a positive but insignificant indirect effect on purchasing decisions through customer satisfaction, whereas service quality has a positive and significant indirect effect on purchasing decisions via customer satisfaction.